Methods of and apparatus for casing a borehole

Abstract

Methods of and apparatus for drilling, casing and / or completing a borehole wherein one or more portions of the borehole are drilled into a formation at a single diameter along the entire length or depth of the or each portion of the borehole. An expandable tubular member is then located within the or each portion of the borehole and radially expanded in the or each portion to line and / or case it or them. Optionally, a corrosion resistant member and / or a service string can be located in the borehole. An advantage of certain embodiments is that a single diameter borehole is formed along the entire length or depth thereof.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims benefit of POT International application number[0002]PCT / GB02 / 01879 filed on Apr. 24, 2002entitled “Method of and Apparatus for Casing a Borehole”, which claims benefit of British application serial number 0109993.6, filed on Apr. 24, 2001.BACKGROUND OF THE INVENTION[0003]1. Field of the Invention[0004]The present invention relates to a method of drilling, casing and / or completing a borehole, and in particular to a method of drilling, casing and / or cladding a borehole. The invention also provides apparatus for completing a borehole. It will be understood that use of the term “borehole” herein is a reference to a bore that has been drilled into a formation to allow the recovery of hydrocarbons (or other fluids) therefrom as is conventional in the art.[0005]2. Description of the Related Art[0006]When a borehole has been drilled into a formation to facilitate, for example, the recovery of hydrocarbons from a well or r...

AI Technical Summary

Benefits of technology

[0018]Preferably, the or each portion of the borehole is drilled at approximately the same diameter as the existing portion(s) of the borehole. Thus, all boreholes are drilled and cased at substantially the same diameter. This is advantageous because it requires only a single sized drill bit to be used instead of a number of different sized bits, and also reduces the amount of time spent in drilling and casing as there is no requirement to change to different sized bits as the borehole increases in depth.

[0045]The or each tubular member is optionally temporarily anchored at an upper or lower end thereof using a mechanical or other anchoring device (e.g. a slip or packer), and facilitates radial expansion thereof.

Problems solved by technology

In addition, the relatively large diameter borehole 10 at the top of the well involves increased costs due to the large drill bits required, heavy equipment for handling the larger casing, and increased volumes of drill fluid that are required.

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